Caption: Killer whale head. The killer whale (Orcinus orca), or orca, is not a whale, but a dolphin. It is found throughout the world's seas, mainly in coastal areas. It can reach up to 9 metres in length and the male's fin can be up to 2 metres tall. It is a social animal living in groups, or pods, that can number up to 40 individuals and is known to protect and care for sick and injured companions. It is a ferocious predator and tends to hunt in packs, often displaying advanced strategies and forward planning. It eats a varied diet, comprising fish, squid, birds and other marine mammals (such as sea lions and whales). Photographed in the Sea of Cortes, Mexico.